我正在按照这个材料在 Android 中实现 QRCode Scanner。
一步一步地,在我的应用程序中实现以下代码后,我在GingerbreadOpenCameraInterface.java类中遇到错误。下图是我面临的错误。

它显示错误为:
  1. The method `getNumberOfCameras()` is undefined for the type Camera
  2. `CameraInfo` cannot be resolved or is not a field
以下是清单文件:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.demo.qrdemo"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
    android:minSdkVersion="9"/>
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.VIBRATE"/>
<uses-permission android:name="android.permission.FLASHLIGHT"/>
<uses-permission android:name="android.permission.READ_CONTACTS"/>
<uses-permission android:name="com.android.browser.permission.READ_HISTORY_BOOKMARKS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
 <uses-feature android:name="android.hardware.camera"/>
 <uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
<uses-feature android:name="android.hardware.camera.flash" android:required="false"/>
<uses-feature android:name="android.hardware.screen.landscape"/>
<uses-feature android:name="android.hardware.wifi" android:required="false"/>
<uses-feature android:name="android.hardware.touchscreen" android:required="false"/>
<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".QRDemo"
        android:label="title_activity_qrdemo" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    <intent-filter>
    <action android:name="com.google.zxing.client.android.SCAN"/>
    <category android:name="android.intent.category.DEFAULT"/>
  </intent-filter>
    </activity>
</application>
谁能帮我解决以下问题?